Body fluid drains are used at so-called drainage sites for draining fluids from cavities in a patient's body, usually during and after surgical procedures. The drainage site may be a natural body cavity or orifice or may be surgically formed. The attainment of a balance of good operative and functional properties in such fluid drains has been a continuing developmental problem. For instance, a tube having a round cross section formed of a rigid material such as metal or plastic will remain open and non-collapsible so that its passageway will generally stay clear. But such rigid drainage devices have long been considered unsatisfactory by surgeons because of the danger of trauma to the tissues and surrounding organs into which they are inserted caused by the non-yieldability of the drainage tube during the patient's body movements.
On the other hand, when drainage tubes are made of a soft yieldable material, they tend to collapse when significant vacuum or suction pressure is applied to them, as is required in many applications, or when the patient's normal body movements or the healing process cause compressive pressures on them.
Several forms of drainage tubes have been developed from soft yieldable materials with internal ribbing and other configurations of stiffening elements to prevent closure and stoppage of the drainage function resulting from collapse during use.
However, the medical profession is still not entirely satisfied with existing drainage tubes and is anxious to have available improved and more foolproof drain tubes. The problem has become more acute since it has also been found desirable to have such drainage devices made from the newer, softer, smoother and more yieldable and flexible materials such as silicone rubber which, when formed as a tube, has an even greater tendency to collapse and create drainage stoppages under normal functional compressive forces.
It is accordingly an object of this invention to provide drainage tubes for body fluids which can be made of the softest and most yieldable materials available such as silicone rubber and which at the same time will continue to function by maintaining a clear drainage passageway to the exterior of the drainage site even when subjected to compressive forces caused by suction pressure applied to the tube and/or by the patient's body movements and the healing process.